This document provides a summary of the expert meeting on methods and tools and on data and observations organized under the Nairobi work programme on impacts, vulnerability and adaptation to climate change. The expert meeting was held in Mexico City, Mexico, from 4 to 7 March 2008. Discussions on methods and tools focused on the application, development and dissemination of methods and tools and the sharing of experiences. Discussions on data and observations focused on promoting improvements in observations, the collection, management and use of observational data, and the exchange of and access to observational data and information. The document contains an overview of good practices, gaps and needs in methods and tools and in data and observations, as well as recommendations and issues for follow-up and further consideration